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74caba7f2a
Dictionaries are only used for SUBSYSTEM and DEVICE properties. The current implementation stores the property names each time they are used. This requires more space than otherwise necessary. Also, because the dictionary entries are currently considered optional, it cannot be relied upon that they are always available, even if the writer wanted to store them. These issues will increase should new dictionary properties be introduced. Rather than storing the subsystem and device properties in the dict ring, introduce a struct dev_printk_info with separate fields to store only the property values. Embed this struct within the struct printk_info to provide guaranteed availability. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/87mu1jl6ne.fsf@jogness.linutronix.de
154 lines
5.8 KiB
Python
154 lines
5.8 KiB
Python
#
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# gdb helper commands and functions for Linux kernel debugging
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#
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# kernel log buffer dump
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#
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# Copyright (c) Siemens AG, 2011, 2012
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#
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# Authors:
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# Jan Kiszka <jan.kiszka@siemens.com>
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#
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# This work is licensed under the terms of the GNU GPL version 2.
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#
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import gdb
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import sys
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from linux import utils
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printk_info_type = utils.CachedType("struct printk_info")
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prb_data_blk_lpos_type = utils.CachedType("struct prb_data_blk_lpos")
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prb_desc_type = utils.CachedType("struct prb_desc")
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prb_desc_ring_type = utils.CachedType("struct prb_desc_ring")
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prb_data_ring_type = utils.CachedType("struct prb_data_ring")
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printk_ringbuffer_type = utils.CachedType("struct printk_ringbuffer")
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atomic_long_type = utils.CachedType("atomic_long_t")
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class LxDmesg(gdb.Command):
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"""Print Linux kernel log buffer."""
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def __init__(self):
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super(LxDmesg, self).__init__("lx-dmesg", gdb.COMMAND_DATA)
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def invoke(self, arg, from_tty):
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inf = gdb.inferiors()[0]
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# read in prb structure
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prb_addr = int(str(gdb.parse_and_eval("(void *)'printk.c'::prb")).split()[0], 16)
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sz = printk_ringbuffer_type.get_type().sizeof
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prb = utils.read_memoryview(inf, prb_addr, sz).tobytes()
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# read in descriptor ring structure
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off = printk_ringbuffer_type.get_type()['desc_ring'].bitpos // 8
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addr = prb_addr + off
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sz = prb_desc_ring_type.get_type().sizeof
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desc_ring = utils.read_memoryview(inf, addr, sz).tobytes()
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# read in descriptor array
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off = prb_desc_ring_type.get_type()['count_bits'].bitpos // 8
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desc_ring_count = 1 << utils.read_u32(desc_ring, off)
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desc_sz = prb_desc_type.get_type().sizeof
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off = prb_desc_ring_type.get_type()['descs'].bitpos // 8
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addr = utils.read_ulong(desc_ring, off)
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descs = utils.read_memoryview(inf, addr, desc_sz * desc_ring_count).tobytes()
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# read in info array
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info_sz = printk_info_type.get_type().sizeof
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off = prb_desc_ring_type.get_type()['infos'].bitpos // 8
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addr = utils.read_ulong(desc_ring, off)
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infos = utils.read_memoryview(inf, addr, info_sz * desc_ring_count).tobytes()
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# read in text data ring structure
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off = printk_ringbuffer_type.get_type()['text_data_ring'].bitpos // 8
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addr = prb_addr + off
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sz = prb_data_ring_type.get_type().sizeof
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text_data_ring = utils.read_memoryview(inf, addr, sz).tobytes()
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# read in text data
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off = prb_data_ring_type.get_type()['size_bits'].bitpos // 8
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text_data_sz = 1 << utils.read_u32(text_data_ring, off)
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off = prb_data_ring_type.get_type()['data'].bitpos // 8
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addr = utils.read_ulong(text_data_ring, off)
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text_data = utils.read_memoryview(inf, addr, text_data_sz).tobytes()
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counter_off = atomic_long_type.get_type()['counter'].bitpos // 8
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sv_off = prb_desc_type.get_type()['state_var'].bitpos // 8
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off = prb_desc_type.get_type()['text_blk_lpos'].bitpos // 8
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begin_off = off + (prb_data_blk_lpos_type.get_type()['begin'].bitpos // 8)
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next_off = off + (prb_data_blk_lpos_type.get_type()['next'].bitpos // 8)
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ts_off = printk_info_type.get_type()['ts_nsec'].bitpos // 8
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len_off = printk_info_type.get_type()['text_len'].bitpos // 8
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# definitions from kernel/printk/printk_ringbuffer.h
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desc_committed = 1
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desc_finalized = 2
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desc_sv_bits = utils.get_long_type().sizeof * 8
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desc_flags_shift = desc_sv_bits - 2
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desc_flags_mask = 3 << desc_flags_shift
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desc_id_mask = ~desc_flags_mask
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# read in tail and head descriptor ids
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off = prb_desc_ring_type.get_type()['tail_id'].bitpos // 8
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tail_id = utils.read_u64(desc_ring, off + counter_off)
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off = prb_desc_ring_type.get_type()['head_id'].bitpos // 8
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head_id = utils.read_u64(desc_ring, off + counter_off)
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did = tail_id
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while True:
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ind = did % desc_ring_count
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desc_off = desc_sz * ind
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info_off = info_sz * ind
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# skip non-committed record
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state = 3 & (utils.read_u64(descs, desc_off + sv_off +
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counter_off) >> desc_flags_shift)
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if state != desc_committed and state != desc_finalized:
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if did == head_id:
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break
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did = (did + 1) & desc_id_mask
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continue
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begin = utils.read_ulong(descs, desc_off + begin_off) % text_data_sz
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end = utils.read_ulong(descs, desc_off + next_off) % text_data_sz
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# handle data-less record
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if begin & 1 == 1:
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text = ""
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else:
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# handle wrapping data block
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if begin > end:
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begin = 0
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# skip over descriptor id
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text_start = begin + utils.get_long_type().sizeof
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text_len = utils.read_u16(infos, info_off + len_off)
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# handle truncated message
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if end - text_start < text_len:
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text_len = end - text_start
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text = text_data[text_start:text_start + text_len].decode(
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encoding='utf8', errors='replace')
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time_stamp = utils.read_u64(infos, info_off + ts_off)
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for line in text.splitlines():
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msg = u"[{time:12.6f}] {line}\n".format(
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time=time_stamp / 1000000000.0,
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line=line)
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# With python2 gdb.write will attempt to convert unicode to
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# ascii and might fail so pass an utf8-encoded str instead.
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if sys.hexversion < 0x03000000:
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msg = msg.encode(encoding='utf8', errors='replace')
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gdb.write(msg)
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if did == head_id:
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break
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did = (did + 1) & desc_id_mask
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LxDmesg()
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